Water use efficiency in oasis agriculture: Have we reached the limit of water-saving technologies?

doi:10.1016/j.regsus.2026.100392

Abstract

Abstract:

Irrigation accounts for the greatest consumption of freshwater, representing a major contributor to water scarcity. Consequently, water-saving technologies (WSTs) are widely applied to improve water use efficiency (WUE). However, growing evidence suggests that at larger scales, these technologies may not always save water but can even exacerbate water scarcity, especially in arid regions. To address these issues, this study examined changes in WUE and crop water productivity (CWP) during 2000-2020 in an oasis agriculture system with widespread adoption of WSTs in arid northwestern China. During the period of widespread adoption of WSTs, WUE increased significantly across 74.3% of the studied cropland, primarily associated with increased gross primary productivity. Early-stage crop yields also increased notably with these practices, albeit with diminishing returns over time. Since 2013, WUE gains have plateaued, and yields of major crops have stagnated or declined. CWP, calculated using equivalent yield and total water consumption, exhibited a breakpoint in 2016. Meanwhile, actual evapotranspiration has continued to rise, which is attributed to sufficient root-zone moisture from drip irrigation that alleviates crop water stress and sustains high transpiration rates. This indicates that further water inputs may no longer yield proportional productivity benefits. Therefore, optimism about achieving greater benefits in oasis agriculture solely through WSTs may be misplaced, highlighting the need for more sustainable and integrated resource management strategies. This study reveals diminishing marginal benefits and emerging limits of WSTs in arid oasis agriculture system, providing a scientific basis for the precise regulation and sustainable utilization of agricultural water resources in arid and semi-arid regions.

Key words: Water use efficiency (WUE), Crop water productivity (CWP), Water-saving technologies (WSTs), Leaf area index (LAI), Gross primary productivity (GPP), Agricultural water consumption

ZHAO Nan, ZHENG Xinjun, DU Lan, LI Yan. Water use efficiency in oasis agriculture: Have we reached the limit of water-saving technologies?[J]. Regional Sustainability, 2026, 7(5): 100392.

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Item	Indicator	Data source
Ecosystem variable	Actual evapotranspiration (ETa) and gross primary productivity (GPP)	PML_V2 dataset (He et al., 2022)
Vegetation index	Leaf area index (LAI)	MOD15A2H
Agricultural data	Cropland area, planting area of the crops, crop unit yield, total production, annual market price, proportion of drip-irrigated land, and irrigation methods	Statistical Yearbook of Xinjiang Production and Construction Corps (Statistical Bureau of Xinjiang Production and Construction Corps, 2001-2021) and Xinjiang Statistical Yearbook (Statistical Bureau of Xinjiang Uygur Autonomous Region, 2001-2021)
Land use data	Land cover	China Land Cover Dataset (CLCD) (Yang and Huang, 2021)
Meteorological data	Precipitation and temperature	China Meteorological Forcing Dataset (CMFD) (2000-2018) (He et al., 2020) and Global Land Data Assimilation System (GLDAS) 2.1 dataset (2019-2020) (Rodell et al., 2004)